1. Field of the Invention
The present invention relates to an imaging apparatus for electronic endoscopes.
2. Description of the Prior Art
The conventional electronic endoscope is mostly configured so as to form a image of an object by a circular lens system 32 on a nearly square image pickup device 31, process this image by an image processing circuit 33 and project a processed image 36 onto a display unit 35 of a TV monitor 34 as illustrated in FIG. 16.
The display unit 15 of the TV monitor 14 has a screen which is designed for an aspect ratio of H:V=4:3 in accordance with the current TV code (NTSC standard). Therefore, only a narrow screen area of the display unit 35 is used wastelessly when the image is projected to a partial area of the screen of the display unit 35 as shown in FIG. 16.
However, the high quality TV set adopts a display unit which has a screen designed for an aspect ratio of H:V=16:9, or is horizontally elongated. In case of an endoscope for the high quality TV set, a large screen area is utilized wastelessly when the square image formed by the electronic endoscope shown in FIG. 16 is projected onto the horizontally elongated screen of the display unit 15.
The problem of such wasteless use of the screen of the display unit can be solved by using a horizontally elongated solid-state image pickup device, but such a solid-state image pickup device will undesirably enlarge an outside diameter of an endoscope.